WO2012120347A1 - Exhaust system having ammonia slip catalyst in egr circuit - Google Patents

Exhaust system having ammonia slip catalyst in egr circuit Download PDF

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Publication number
WO2012120347A1
WO2012120347A1 PCT/IB2012/000303 IB2012000303W WO2012120347A1 WO 2012120347 A1 WO2012120347 A1 WO 2012120347A1 IB 2012000303 W IB2012000303 W IB 2012000303W WO 2012120347 A1 WO2012120347 A1 WO 2012120347A1
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WO
WIPO (PCT)
Prior art keywords
exhaust system
catalyst
exhaust gas
oxidation catalyst
egr
Prior art date
Application number
PCT/IB2012/000303
Other languages
French (fr)
Inventor
Guy Richard Chandler
Neil Robert Collins
Paul Richard Phillips
Original Assignee
Johnson Matthey Public Limited Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Johnson Matthey Public Limited Company filed Critical Johnson Matthey Public Limited Company
Priority to CN201280011962.6A priority Critical patent/CN103402610B/en
Priority to RU2013144726/06A priority patent/RU2591753C2/en
Priority to KR1020137022919A priority patent/KR101986388B1/en
Priority to EP12711446.0A priority patent/EP2683468B1/en
Priority to JP2013557182A priority patent/JP6169000B2/en
Priority to US14/003,503 priority patent/US20140033685A1/en
Priority to BR112013021254-3A priority patent/BR112013021254B1/en
Publication of WO2012120347A1 publication Critical patent/WO2012120347A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9404—Removing only nitrogen compounds
    • B01D53/9436—Ammonia
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/54—Nitrogen compounds
    • B01D53/56—Nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/90—Injecting reactants
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9404—Removing only nitrogen compounds
    • B01D53/9409—Nitrogen oxides
    • B01D53/9413—Processes characterised by a specific catalyst
    • B01D53/9418—Processes characterised by a specific catalyst for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9459—Removing one or more of nitrogen oxides, carbon monoxide, or hydrocarbons by multiple successive catalytic functions; systems with more than one different function, e.g. zone coated catalysts
    • B01D53/9463—Removing one or more of nitrogen oxides, carbon monoxide, or hydrocarbons by multiple successive catalytic functions; systems with more than one different function, e.g. zone coated catalysts with catalysts positioned on one brick
    • B01D53/9472—Removing one or more of nitrogen oxides, carbon monoxide, or hydrocarbons by multiple successive catalytic functions; systems with more than one different function, e.g. zone coated catalysts with catalysts positioned on one brick in different zones
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/033—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices
    • F01N3/035—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices with catalytic reactors, e.g. catalysed diesel particulate filters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/105—General auxiliary catalysts, e.g. upstream or downstream of the main catalyst
    • F01N3/106—Auxiliary oxidation catalysts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
    • F02M26/35—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with means for cleaning or treating the recirculated gases, e.g. catalysts, condensate traps, particle filters or heaters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/10—Noble metals or compounds thereof
    • B01D2255/102—Platinum group metals
    • B01D2255/1021—Platinum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01D2255/00—Catalysts
    • B01D2255/10—Noble metals or compounds thereof
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    • B01D2255/1023—Palladium
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B01D2255/20—Metals or compounds thereof
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    • B01D2255/20738—Iron
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
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    • B01D2255/20761—Copper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/50—Zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/90—Physical characteristics of catalysts
    • B01D2255/915—Catalyst supported on particulate filters
    • B01D2255/9155—Wall flow filters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/01—Engine exhaust gases
    • B01D2258/012—Diesel engines and lean burn gasoline engines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/56—Platinum group metals
    • B01J23/63—Platinum group metals with rare earths or actinides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/70—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65
    • B01J29/72—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65 containing iron group metals, noble metals or copper
    • B01J29/76—Iron group metals or copper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/024—Multiple impregnation or coating
    • B01J37/0246—Coatings comprising a zeolite
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2510/00—Surface coverings
    • F01N2510/06—Surface coverings for exhaust purification, e.g. catalytic reaction
    • F01N2510/068—Surface coverings for exhaust purification, e.g. catalytic reaction characterised by the distribution of the catalytic coatings
    • F01N2510/0682—Surface coverings for exhaust purification, e.g. catalytic reaction characterised by the distribution of the catalytic coatings having a discontinuous, uneven or partially overlapping coating of catalytic material, e.g. higher amount of material upstream than downstream or vice versa
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2510/00—Surface coverings
    • F01N2510/06—Surface coverings for exhaust purification, e.g. catalytic reaction
    • F01N2510/068—Surface coverings for exhaust purification, e.g. catalytic reaction characterised by the distribution of the catalytic coatings
    • F01N2510/0684—Surface coverings for exhaust purification, e.g. catalytic reaction characterised by the distribution of the catalytic coatings having more than one coating layer, e.g. multi-layered coatings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/02—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor
    • F01N2560/026—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor for measuring or detecting NOx
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
    • F01N2570/18—Ammonia
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the present invention relates to an exhaust system for a vehicular lean burn internal combustion engine that emits oxides of nitrogen and particulate matter.
  • NO x nitrogen
  • N0 2 nitrogen dioxide
  • N 2 0 nitrous oxide
  • SCR Selective Catalytic Reduction
  • An SCR process involves the conversion of NO x , in the presence of a catalyst and with the aid of a reducing agent, into elemental nitrogen (N 2 ) and water.
  • a gaseous reductant typically anhydrous ammonia, aqueous ammonia, or urea
  • the reductant is absorbed onto a catalyst and the NO x reduction reaction takes place as the gases pass through or over the catalyzed substrate.
  • an ammonia oxidation catalyst also known as an ammonia slip catalyst or "ASC" is installed downstream of the SCR catalyst for this purpose.
  • an SCR catalyst to a filter substrate (SCRF) serves to reduce the overall size of an exhaust treatment system by allowing one substrate to serve two functions, namely catalytic conversion of NO x by the SCR catalyst and removal of soot by the filter.
  • SCRF filter substrate
  • these two functions were separately performed by an SCR and a catalytic soot filter (CSF), respectively.
  • Exhaust gas recirculation is a method for reducing NO x emissions from an engine by returning a portion of an engine's exhaust gas to the engine combustion chambers via the air intake. EGR works by lowering the oxygen concentration in the combustion chamber, thereby decreasing the peak temperature of the fuel combustion flame as well as through heat absorption. EGR is not a new technology - it has been used since the mid-1970s in gasoline fueled passenger car engines. Following the gasoline application, EGR was also introduced to diesel passenger cars and - from the early 2000s - to heavy-duty diesel engines.
  • EGR exhaust gas pressure downstream of the filter
  • high pressure loop EGR in which the exhaust gas is recirculated from upstream of a turbocharger to ensure that exhaust gas will flow from the former to the latter
  • low pressure loop EGR also called long loop EGR
  • Exhaust gas pressure downstream of the filter is generally lower than at the intake manifold, allowing exhaust gas to flow from the former to the latter location.
  • an EGR valve is set to recirculate approximately 50% of the exhaust gas to the engine.
  • Exhaust gas emitted from the engine during EGR has lower oxygen content but no higher NO x content than exhaust gas recirculated from the exhaust system to the engine.
  • Ammonia slip catalysts have been used to prevent NH 3 entering the atmosphere (i.e., via the tailpipe of an automobile), but have not been used in the EGR system itself.
  • the EGR-ASC should have high selectivity to form N 2 and have low backpressure.
  • the invention includes an exhaust system for a vehicular lean burn internal combustion engine that emits oxides of nitrogen (NO*) and particulate matter (PM), and a lean-burn internal combustion engine containing the exhaust system.
  • the system comprises a NO x reduction catalyst for reducing NO x in the presence of a nitrogenous reductant, means for introducing the nitrogenous reductant into a flowing exhaust gas, a filter for removing PM from exhaust gas flowing in the exhaust system and a low pressure exhaust gas recirculation (EGR) circuit for connecting the exhaust system downstream of the filter to an air intake of the engine.
  • the EGR circuit comprises an ammonia oxidation catalyst.
  • the ammonia oxidation catalyst serves to oxidize most, if not all, of the ammonia in the exhaust gas recirculation loop prior to exhaust gas entering the engine.
  • the ammonia oxidation catalyst reduces the concentration of ammonia slip from the NO x reduction reaction, the release of ammonia from the catalyst surface during rapid temperature increases, or from the use of a stoichiometric excess of reductant.
  • FIG. 1 is a schematic flow diagram of one embodiment of the invention.
  • the invention is an exhaust system that comprises a NO x reduction catalyst for reducing NO x in the presence of a nitrogenous reductant, means for introducing the nitrogenous reductant into a flowing exhaust gas, a filter for removing PM from exhaust gas flowing in the exhaust system and a low pressure exhaust gas recirculation (EGR) circuit for connecting the exhaust system downstream of the filter to an air intake of the engine.
  • the EGR circuit comprises an ammonia oxidation catalyst.
  • Suitable NO x reduction catalysts known in the art include selective catalytic reduction (SCR) catalysts, which are particularly useful for selectively catalyzing catalyzes the reduction of NO x using a nitrogenous reductant.
  • SCR selective catalytic reduction
  • Suitable selective catalytic reduction catalysts include transition metal promoted molecular sieves such as aluminosilicate zeolites and silicoaluminophosphates.
  • Suitable transition metal promoters include Cr, Ce, Mn, Fe, Co, Ni and Cu and mixtures of any two or more thereof.
  • Preferred molecular sieve catalysts include CuCHA, such as Cu-SAPO-34, Cu- SSZ-13, and Fe-Beta zeolite, where either the Fe is present in the framework of the molecular sieve structure and/or otherwise associated e.g. ion-exchanged with the framework structure.
  • Fe-WO x -Zr0 2 can be used as an active non-molecular sieve SCR catalyst.
  • the nitrogenous reductant for use in the system can be ammonia per se, hydrazine or an ammonia precursor selected from the group consisting of urea ((NH 2 ) 2 CO), ammonium carbonate, ammonium carbamate, ammonium hydrogen carbonate and ammonium formate.
  • the nitrogenous reductant is added to the flowing exhaust gas by any suitable means for introducing the reductant into the exhaust gas.
  • suitable means include an injector, sprayer, or feeder, and is preferably an injector. Such means are well known in the art.
  • the system may comprise means for controlling the introduction of nitrogenous reductant into the exhaust gas in order to reduce NO x therein.
  • the control means comprises an electronic control unit, optionally an engine control unit.
  • the control means may comprise a NO x sensor located downstream of the NO x reduction catalyst.
  • the system also comprises a filter, preferably a wall-flow filter.
  • the filter and NO x reduction catalyst can be arranged in any suitable configuration.
  • the NO x reduction catalyst is located downstream of the filter.
  • the means for introducing reductant into a flowing exhaust gas is suitably located between the filter and the NO x reduction catalyst.
  • the NO x reduction catalyst is located on the filter, most preferably in the form of a selective catalytic reduction filter (known as an SCRF).
  • SCRF selective catalytic reduction filter
  • the NO x reduction catalyst can be formulated as a washcoat that permeates the walls of the filter. This can be done, for example, by milling the catalyst to an average particle size of ⁇ 5pm.
  • the means for introducing reductant into a flowing exhaust gas is suitably located upstream of the filter.
  • a second ammonia oxidation catalyst may be disposed downstream of the NO x reduction catalyst and upstream of the EGR, relative to the direction of exhaust gas flow through the system.
  • the second ammonia oxidation catalyst is located at the rear of the selective catalytic reduction filter such that the filter comprises a selective catalytic reduction catalyst throughout and a rear zone, relative the direction of exhaust gas flow through the system, that is coated with the second ammonia oxidation catalyst.
  • the second ammonia oxidation catalyst preferably comprises platinum and/or palladium on a metal oxide such as alumina.
  • an NO oxidation catalyst for oxidizing NO to nitrogen dioxide is located upstream of the filter and/or the NO x reduction catalyst.
  • the NO oxidation catalyst preferably comprises a platinum group metal, most preferably platinum.
  • the system also comprises a low pressure exhaust gas recirculation (EGR) circuit for connecting the exhaust system downstream of the filter to an air intake of the engine, wherein the EGR circuit comprises an ammonia oxidation catalyst (also known as an ammonia slip catalyst or "ASC").
  • EGR exhaust gas recirculation
  • the ammonia oxidation catalyst material should be selected to favor the oxidation of ammonia instead of the formation of NO x or N 2 0.
  • Preferred catalyst materials include platinum, palladium, or a combination thereof, with platinum or a platinum/palladium combination being preferred.
  • the ammonia oxidation catalyst comprises platinum and/or palladium supported on a metal oxide.
  • the catalyst is disposed on a high surface area support, including but not limited to alumina.
  • the ammonia oxidation catalyst is applied to a substrate, preferably substrates that are designed to provide large contact surface with minimal backpressure.
  • the ammonia oxidation catalyst is located in or on a flow-through monolith substrate, such as flow-through metallic or cordierite honeycombs.
  • a preferred flow-through monolith substrate has between about 25 and about 300 cells per square inch (cpsi) to ensure low backpressure. Achieving low backpressure is particularly important to minimize the ammonia oxidation catalyst's effect on the low-pressure EGR performance.
  • An ammonia oxidation catalyst can be applied to the flow-through monolith substrate as a washcoat, preferably to achieve a loading of about 0.3 to 2.3 g/in 3 .
  • the front part of the substrate can be coated with just SCR coating, and the rear coated with SCR and an ammonia oxidation catalyst composition such as Pt or Pt/Pd on an alumina support.
  • the invention provides a lean-burn internal combustion engine comprising an exhaust system according to the invention.
  • the lean- burn internal combustion engine can be a lean-burn gasoline or a diesel engine, but the engine may also run on alternative fuels such as liquid petroleum gas, natural gas or comprise bio-fuels or gas -to-liquid products.
  • the lean- burn internal combustion engine is a compression ignition engine powered e.g. by diesel fuel.
  • Figure 1 is a schematic diagram of a vehicular lean-burn internal combustion engine comprising an exhaust system according to a first embodiment of the invention featuring an ammonia oxidation catalyst component disposed in an exhaust gas recirculation circuit.
  • a diesel engine 12 comprising an exhaust system 10 according to the present invention.
  • the exhaust system comprises an exhaust line 14 wherein aftertreatment components are disposed in series.
  • the NO oxidation catalyst 16 comprises a ceramic flow-through substrate monolith coated with a NO oxidation catalyst composition comprising a platinum rich combination of platinum and palladium supported on an alumina-based high surface area support material.
  • a ceramic wall-flow filter 20 comprising a washcoat of Cu-SSZ-13 selective catalytic reduction catalyst is disposed downstream of NO oxidation catalyst 16.
  • An optional ammonia oxidation clean-up or slip catalyst 36 may be coated on a downstream end of the SCR catalyst monolith substrate.
  • Means (injector 22) is provided for introducing nitrogenous reductant fluid (urea 26) from reservoir 24 into exhaust gas carried in the exhaust line 14.
  • Injector 22 is controlled using valve 28, which valve is in turn controlled by electronic control unit 30 (valve control represented by dotted line).
  • Electronic control unit 30 receives closed loop feedback control input from a NO x sensor 32 located downstream of the SCR catalyst.
  • Low pressure exhaust gas recirculation circuit 17 comprises an exhaust gas recirculation valve 18 also controlled by the electronic control unit 30.
  • ASC 19 Disposed within the exhaust gas recirculation circuit, ASC 19 comprises a metallic flow-through substrate monolith coated with a Pt or Pt/Pd composition supported on alumina. The ASC 19 serves to oxidize ammonia that would otherwise enter the engine.

Abstract

An exhaust system for a vehicular lean burn internal combustion engine that emits oxides of nitrogen (NOx) and particulate matter (PM) is disclosed. The system comprises a NOx reduction catalyst for reducing NOx in the presence of a nitrogenous reductant, means for introducing the nitrogenous reductant into a flowing exhaust gas, a filter for removing PM from exhaust gas flowing in the exhaust system and a low pressure exhaust gas recirculation (EGR) circuit for connecting the exhaust system downstream of the filter to an air intake of the engine. The EGR circuit comprises an ammonia oxidation catalyst.

Description

EXHAUST SYSTEM HAVING AMMONIA SLIP CATALYST IN EGR CIRCUIT
FIELD OF THE INVENTION
The present invention relates to an exhaust system for a vehicular lean burn internal combustion engine that emits oxides of nitrogen and particulate matter.
BACKGROUND OF THE INVENTION
One of the most burdensome components of vehicular exhaust gas are the oxides of nitrogen (NOx), which include nitric oxide (NO), nitrogen dioxide (N02), and nitrous oxide (N20). The production of NOx is particularly problematic for lean burn engines, such as diesel engines. To mitigate the environmental impact of NOx in exhaust gas, it is desirable to eliminate these undesirable components, preferably by a process that does not generate other noxious or toxic substances.
One method for converting NOx in a diesel exhaust gas into more benign substances is commonly referred to as Selective Catalytic Reduction (SCR). An SCR process involves the conversion of NOx, in the presence of a catalyst and with the aid of a reducing agent, into elemental nitrogen (N2) and water. In an SCR process, a gaseous reductant, typically anhydrous ammonia, aqueous ammonia, or urea, is added to an exhaust gas stream prior to contacting the catalyst. The reductant is absorbed onto a catalyst and the NOx reduction reaction takes place as the gases pass through or over the catalyzed substrate. However, to maximize the conversion efficiency, it is often necessary to add more than a stoichiometric amount of ammonia to the gas stream. This excess of ammonia would be detrimental to the environment if released into the atmosphere, and thus should be eliminated. In conventional exhaust systems, an ammonia oxidation catalyst (also known as an ammonia slip catalyst or "ASC") is installed downstream of the SCR catalyst for this purpose.
To reduce the amount of space required for an exhaust system, it is often desirable to design individual exhaust components to perform more than one function. For example, applying an SCR catalyst to a filter substrate (SCRF) serves to reduce the overall size of an exhaust treatment system by allowing one substrate to serve two functions, namely catalytic conversion of NOx by the SCR catalyst and removal of soot by the filter. Conventionally, these two functions were separately performed by an SCR and a catalytic soot filter (CSF), respectively.
Exhaust gas recirculation (EGR) is a method for reducing NOx emissions from an engine by returning a portion of an engine's exhaust gas to the engine combustion chambers via the air intake. EGR works by lowering the oxygen concentration in the combustion chamber, thereby decreasing the peak temperature of the fuel combustion flame as well as through heat absorption. EGR is not a new technology - it has been used since the mid-1970s in gasoline fueled passenger car engines. Following the gasoline application, EGR was also introduced to diesel passenger cars and - from the early 2000s - to heavy-duty diesel engines.
Generally, there are two exhaust system arrangements comprising EGR: (i) high pressure loop EGR, in which the exhaust gas is recirculated from upstream of a turbocharger to ensure that exhaust gas will flow from the former to the latter; and (ii) low pressure loop EGR (also called long loop EGR), where exhaust gas is often recirculated from downstream of a particulate filter, allowing all the exhaust gas to be utilised in the turbo. Exhaust gas pressure downstream of the filter is generally lower than at the intake manifold, allowing exhaust gas to flow from the former to the latter location.
In use, particularly during cold start in a vehicle configured to meet the MVEG-A drive cycle, an EGR valve is set to recirculate approximately 50% of the exhaust gas to the engine. Exhaust gas emitted from the engine during EGR has lower oxygen content but no higher NOx content than exhaust gas recirculated from the exhaust system to the engine.
While SCRF systems offer tremendous advantage for improved NOx conversion compared to conventional, separate CSF + SCR catalyst systems, the maximum advantage is gained by using so-called low pressure EGR, whereby the EGR is taken after the SCRF. However, a problem can be encountered that ammonia slips from the SCRF (due to non-ideal gas or NH3, or NH3-source such as urea, or due to changes in operating conditions that results in release of stored ammonia from the SCRF). Ammonia or NH3- source species then enter the EGR system. These species can cause damage to the EGR system. Ammonia slip catalysts have been used to prevent NH3 entering the atmosphere (i.e., via the tailpipe of an automobile), but have not been used in the EGR system itself. The EGR-ASC should have high selectivity to form N2 and have low backpressure.
SUMMARY OF THE INVENTION
The invention includes an exhaust system for a vehicular lean burn internal combustion engine that emits oxides of nitrogen (NO*) and particulate matter (PM), and a lean-burn internal combustion engine containing the exhaust system. The system comprises a NOx reduction catalyst for reducing NOx in the presence of a nitrogenous reductant, means for introducing the nitrogenous reductant into a flowing exhaust gas, a filter for removing PM from exhaust gas flowing in the exhaust system and a low pressure exhaust gas recirculation (EGR) circuit for connecting the exhaust system downstream of the filter to an air intake of the engine. The EGR circuit comprises an ammonia oxidation catalyst. The ammonia oxidation catalyst serves to oxidize most, if not all, of the ammonia in the exhaust gas recirculation loop prior to exhaust gas entering the engine. Thus, the ammonia oxidation catalyst reduces the concentration of ammonia slip from the NOx reduction reaction, the release of ammonia from the catalyst surface during rapid temperature increases, or from the use of a stoichiometric excess of reductant.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic flow diagram of one embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The invention is an exhaust system that comprises a NOx reduction catalyst for reducing NOx in the presence of a nitrogenous reductant, means for introducing the nitrogenous reductant into a flowing exhaust gas, a filter for removing PM from exhaust gas flowing in the exhaust system and a low pressure exhaust gas recirculation (EGR) circuit for connecting the exhaust system downstream of the filter to an air intake of the engine. The EGR circuit comprises an ammonia oxidation catalyst.
Suitable NOx reduction catalysts known in the art include selective catalytic reduction (SCR) catalysts, which are particularly useful for selectively catalyzing catalyzes the reduction of NOx using a nitrogenous reductant. Suitable selective catalytic reduction catalysts include transition metal promoted molecular sieves such as aluminosilicate zeolites and silicoaluminophosphates. Suitable transition metal promoters include Cr, Ce, Mn, Fe, Co, Ni and Cu and mixtures of any two or more thereof. Preferred molecular sieve catalysts include CuCHA, such as Cu-SAPO-34, Cu- SSZ-13, and Fe-Beta zeolite, where either the Fe is present in the framework of the molecular sieve structure and/or otherwise associated e.g. ion-exchanged with the framework structure. Fe-WOx-Zr02 can be used as an active non-molecular sieve SCR catalyst.
The nitrogenous reductant for use in the system can be ammonia per se, hydrazine or an ammonia precursor selected from the group consisting of urea ((NH2)2CO), ammonium carbonate, ammonium carbamate, ammonium hydrogen carbonate and ammonium formate.
The nitrogenous reductant is added to the flowing exhaust gas by any suitable means for introducing the reductant into the exhaust gas. Suitable means include an injector, sprayer, or feeder, and is preferably an injector. Such means are well known in the art.
The system may comprise means for controlling the introduction of nitrogenous reductant into the exhaust gas in order to reduce NOx therein. In one embodiment, the control means comprises an electronic control unit, optionally an engine control unit. Furthermore, the control means may comprise a NOx sensor located downstream of the NOx reduction catalyst.
The system also comprises a filter, preferably a wall-flow filter.
The filter and NOx reduction catalyst can be arranged in any suitable configuration. In one embodiment, the NOx reduction catalyst is located downstream of the filter. In this embodiment the means for introducing reductant into a flowing exhaust gas is suitably located between the filter and the NOx reduction catalyst.
Preferably, the NOx reduction catalyst is located on the filter, most preferably in the form of a selective catalytic reduction filter (known as an SCRF). Where the filter is a wall-flow filter, the NOx reduction catalyst can be formulated as a washcoat that permeates the walls of the filter. This can be done, for example, by milling the catalyst to an average particle size of < 5pm. In this embodiment the means for introducing reductant into a flowing exhaust gas is suitably located upstream of the filter.
Preferably, a second ammonia oxidation catalyst may be disposed downstream of the NOx reduction catalyst and upstream of the EGR, relative to the direction of exhaust gas flow through the system. Most preferably, the second ammonia oxidation catalyst is located at the rear of the selective catalytic reduction filter such that the filter comprises a selective catalytic reduction catalyst throughout and a rear zone, relative the direction of exhaust gas flow through the system, that is coated with the second ammonia oxidation catalyst. The second ammonia oxidation catalyst preferably comprises platinum and/or palladium on a metal oxide such as alumina.
In a preferred embodiment, an NO oxidation catalyst for oxidizing NO to nitrogen dioxide is located upstream of the filter and/or the NOx reduction catalyst. The NO oxidation catalyst preferably comprises a platinum group metal, most preferably platinum.
The system also comprises a low pressure exhaust gas recirculation (EGR) circuit for connecting the exhaust system downstream of the filter to an air intake of the engine, wherein the EGR circuit comprises an ammonia oxidation catalyst (also known as an ammonia slip catalyst or "ASC").
Preferably, the ammonia oxidation catalyst material should be selected to favor the oxidation of ammonia instead of the formation of NOx or N20. Preferred catalyst materials include platinum, palladium, or a combination thereof, with platinum or a platinum/palladium combination being preferred. Preferably, the ammonia oxidation catalyst comprises platinum and/or palladium supported on a metal oxide. Preferably, the catalyst is disposed on a high surface area support, including but not limited to alumina. In certain embodiments, the ammonia oxidation catalyst is applied to a substrate, preferably substrates that are designed to provide large contact surface with minimal backpressure. Preferably, the ammonia oxidation catalyst is located in or on a flow-through monolith substrate, such as flow-through metallic or cordierite honeycombs. For example, a preferred flow-through monolith substrate has between about 25 and about 300 cells per square inch (cpsi) to ensure low backpressure. Achieving low backpressure is particularly important to minimize the ammonia oxidation catalyst's effect on the low-pressure EGR performance.
An ammonia oxidation catalyst can be applied to the flow-through monolith substrate as a washcoat, preferably to achieve a loading of about 0.3 to 2.3 g/in3. To provide further NOx conversion, the front part of the substrate can be coated with just SCR coating, and the rear coated with SCR and an ammonia oxidation catalyst composition such as Pt or Pt/Pd on an alumina support.
According to a further aspect, the invention provides a lean-burn internal combustion engine comprising an exhaust system according to the invention. The lean- burn internal combustion engine can be a lean-burn gasoline or a diesel engine, but the engine may also run on alternative fuels such as liquid petroleum gas, natural gas or comprise bio-fuels or gas -to-liquid products. In a particular embodiment, the lean- burn internal combustion engine is a compression ignition engine powered e.g. by diesel fuel.
In order that the invention may be more fully understood, the following Examples are provided by way of illustration only and with reference to the accompanying drawing.
EXAMPLES
Figure 1 is a schematic diagram of a vehicular lean-burn internal combustion engine comprising an exhaust system according to a first embodiment of the invention featuring an ammonia oxidation catalyst component disposed in an exhaust gas recirculation circuit.
Referring to Figure 1, there is shown a diesel engine 12 comprising an exhaust system 10 according to the present invention. The exhaust system comprises an exhaust line 14 wherein aftertreatment components are disposed in series. The NO oxidation catalyst 16 comprises a ceramic flow-through substrate monolith coated with a NO oxidation catalyst composition comprising a platinum rich combination of platinum and palladium supported on an alumina-based high surface area support material.
A ceramic wall-flow filter 20 comprising a washcoat of Cu-SSZ-13 selective catalytic reduction catalyst is disposed downstream of NO oxidation catalyst 16. An optional ammonia oxidation clean-up or slip catalyst 36 may be coated on a downstream end of the SCR catalyst monolith substrate. Means (injector 22) is provided for introducing nitrogenous reductant fluid (urea 26) from reservoir 24 into exhaust gas carried in the exhaust line 14. Injector 22 is controlled using valve 28, which valve is in turn controlled by electronic control unit 30 (valve control represented by dotted line). Electronic control unit 30 receives closed loop feedback control input from a NOx sensor 32 located downstream of the SCR catalyst.
Low pressure exhaust gas recirculation circuit 17 comprises an exhaust gas recirculation valve 18 also controlled by the electronic control unit 30. Disposed within the exhaust gas recirculation circuit, ASC 19 comprises a metallic flow-through substrate monolith coated with a Pt or Pt/Pd composition supported on alumina. The ASC 19 serves to oxidize ammonia that would otherwise enter the engine.

Claims

We claim :
1. An exhaust system for a vehicular lean burn internal combustion engine that emits oxides of nitrogen (NOx) and particulate matter (PM), the system comprising a NOx reduction catalyst for reducing NOx in the presence of a nitrogenous reductant, means for introducing the nitrogenous reductant into a flowing exhaust gas, a filter for removing PM from exhaust gas flowing in the exhaust system and a low pressure exhaust gas recirculation (EGR) circuit for connecting the exhaust system downstream of the filter to an air intake of the engine, wherein the EGR circuit comprises an ammonia oxidation catalyst.
2. The exhaust system of claim 1, wherein the NOx reduction catalyst is a selective catalytic reduction catalyst comprising a transition metal promoted molecular sieve.
3. The exhaust system of claim 1, wherein the nitrogenous reductant is ammonia, hydrazine or an ammonia precursor selected from the group consisting of urea ((Nh^hCO), ammonium carbonate, ammonium carbamate, ammonium hydrogen carbonate and ammonium formate.
4. The exhaust system of claim 1, wherein the NOx reduction catalyst is located on the filter.
5. The exhaust system of claim 1, wherein the ammonia oxidation catalyst comprises platinum and/or palladium supported on a metal oxide.
6. The exhaust system of claim 5, wherein the ammonia oxidation catalyst is located in or on a flow-through monolith substrate.
7. The exhaust system of claim 6, wherein the substrate is metallic.
8. The exhaust system of claim 6, wherein the substrate comprises about 25 to about 300 parallel channels per square inch of cross-sectional area.
9. The exhaust system of claim 6, wherein the substrate is loaded with about 0.3 to about 2.3 g/in3 of an ammonia oxidation catalyst.
10. The exhaust system of claim 6, wherein the substrate has a front and a rear, relative to the direction of gas flow through the substrate, and wherein the front is loaded with a selective catalytic reduction (SCR) catalyst and the rear is loaded with a SCR and an ammonia oxidation catalyst composition.
11. The exhaust system of claim 1 further comprising a second ammonia oxidation catalyst disposed downstream of the SCRF and upstream of the EGR, relative to the direction of exhaust gas flow through the system.
12. A lean-burn internal combustion engine comprising an exhaust system according to any preceding claim.
PCT/IB2012/000303 2011-03-07 2012-02-21 Exhaust system having ammonia slip catalyst in egr circuit WO2012120347A1 (en)

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CN201280011962.6A CN103402610B (en) 2011-03-07 2012-02-21 Exhaust system having ammonia slip catalyst in EGR circuit
RU2013144726/06A RU2591753C2 (en) 2011-03-07 2012-02-21 Exhaust system comprising catalyst for preventing penetration of ammonia in exhaust gas recycling circuit
KR1020137022919A KR101986388B1 (en) 2011-03-07 2012-02-21 Exhaust system having ammonia slip catalyst in egr circuit
EP12711446.0A EP2683468B1 (en) 2011-03-07 2012-02-21 Exhaust system having ammonia slip catalyst in egr circuit
JP2013557182A JP6169000B2 (en) 2011-03-07 2012-02-21 Exhaust system having ammonia slip catalyst in EGR circuit
US14/003,503 US20140033685A1 (en) 2011-03-07 2012-02-21 Exhaust system having ammonia slip catalyst and egr circuit
BR112013021254-3A BR112013021254B1 (en) 2011-03-07 2012-02-21 exhaust system for a lean-burn vehicle internal combustion engine; and, lean-burn internal combustion engine

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EP2683468B1 (en) 2017-07-19
KR101986388B1 (en) 2019-06-05
CN103402610B (en) 2017-02-22
JP2014510867A (en) 2014-05-01
RU2591753C2 (en) 2016-07-20
RU2013144726A (en) 2015-04-20
JP6169000B2 (en) 2017-07-26
BR112013021254A2 (en) 2020-06-30
EP2683468A1 (en) 2014-01-15
US20140033685A1 (en) 2014-02-06
BR112013021254B1 (en) 2021-05-04
CN103402610A (en) 2013-11-20
KR20140017570A (en) 2014-02-11

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